More than 30,000 people across the Gulf Coast are likely to seek temporary shelter as Tropical Storm Harvey continues to drench southeastern Texas and Louisiana with heavy rains and surging floodwaters. (August 29, 2017) (Sign up for our free video newsletter here http://bit.ly/2n6VKPR)

More than 30,000 people across the Gulf Coast are likely to seek temporary shelter as Tropical Storm Harvey continues to drench southeastern Texas and Louisiana with heavy rains and surging floodwaters. (August 29, 2017) (Sign up for our free video newsletter here http://bit.ly/2n6VKPR)

To those who assess climate change based on science, not politics, Harvey’s late strengthening and biblical rainfall represented not a freak occurrence but warnings of an ominous trend. That conclusion should scare many politicians in Washington and every politician in Florida.

Trump, however, withdrew the United States from the Paris climate accord. The Scott administration has banned the term “climate change” in official communications and public comment. “I’m not a scientist,” Scott said, trying to evade the climate change issue. He’s also not a doctor, but the governor has signed bills related to abortion that doctors call unnecessary and invasive.

So as Houston officials literally try to keep their residents above water, let’s see what actual scientists take from Harvey.

As noted, Harvey surprised forecasters by intensifying quickly as the storm approached the Texas coast. Though hurricanes typically lose strength as they move toward land and away from the water that sustains them, the reverse can happen. It happened with Hurricane Charley, which struck the west coast of Florida in 2004. Intensity forecasts also are less reliable than track forecasts.

As our planet warms, however, the potential for such quick intensification grows. Kerry Emanuel, who teaches atmospheric sciences at the Massachusetts Institute of Technology, has researched this phenomenon.

“Hurricanes are powered by the evaporation of sea water," Emanuel told National Geographic this week. "Water evaporates faster from a hot surface than a cold surface." He studied 6,000 simulated storms and how they might evolve over the rest of the century if the greenhouse gases that cause global warming continue to rise at current rates. Emanuel then compared the results to conditions in the last century.

Based on the comparison, Emanuel concluded that a 70-mile-per-hour increase in the 24 hours before landfall might have occurred once in a century under historic conditions. If the planet keeps sweating for another 83 years, that rapid, dangerous strengthening might happen every five or 10 years.

As for rainfall, a warmer atmosphere can hold more water. The link may seem ironic, since climate change also produces more inland drought. Yet as the magazine noted in its Harvey report, “Every scientist contacted by National Geographic was in agreement that the volume of rain from Harvey was almost certainly driven up by temperature increases from human carbon-dioxide emissions.”

All credible evidence, however, shows that climate change can make hurricanes much more dangerous. With Hurricane Sandy in 2012 and now Harvey, most of the damage came not from wind — as with Andrew — but from storm surge and flooding.

Rising seas mean more dangerous surges. High moisture can mean more trouble than comparatively low winds. In 2012, Isaac barely got to hurricane strength over and near Florida, but the resultant flooding caused the federal government to declare a major disaster in the state.

Worldwide, climate change is a security threat because of all the people — many of them poor — it could displace. In Florida, climate change is an economic threat. Though the answer for now to The Wall Street Journal’s post-Wilma, post-real estate bust headline “Is Florida Over?” is no, the state remains vulnerable. As Harvey shows, so do many parts of the country.

A responsible president would make climate change response a priority, not use bogus claims about lost jobs to justify withdrawing from the Paris agreement, as Trump did. A responsible president would not seek to cut the Federal Emergency Management Agency’s budget, as Trump did.

A responsible governor would listen to fellow Republicans like former Treasury Secretary Henry Paulson. He called climate change denial “Radical Risk Taking.” A responsible governor would have told Republican Attorney General Pam Bondi not to challenge President Obama’s Clean Power Plan.

Trump and Scott, though, are ideologues on this issue. Trump performs for his base, where climate change skepticism runs deep. Maybe those supporters see climate change as a danger that is decades off and doesn’t threaten them. Maybe they were thinking that in Houston.